'commit'

TangDou/LuoGuBook/P1047_1.cpp

@@ -0,0 +1,23 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+const int N = 10010;
+int b[N];
+int l;
+int m;
+
+int cnt;
+
+int main() {
+    scanf("%d %d", &l, &m);
+    while (m--) {
+        int u, v;
+        scanf("%d %d", &u, &v);
+        for (int i = u; i <= v; i++) b[i]++;
+    }
+    for (int i = 0; i <= l; i++)
+        if (b[i] == 0) cnt++;
+
+    printf("%d", cnt);
+    return 0;
+}